EP1237393A2 - Lautsprecher und Lautsprechersystem - Google Patents

Lautsprecher und Lautsprechersystem Download PDF

Info

Publication number
EP1237393A2
EP1237393A2 EP02001525A EP02001525A EP1237393A2 EP 1237393 A2 EP1237393 A2 EP 1237393A2 EP 02001525 A EP02001525 A EP 02001525A EP 02001525 A EP02001525 A EP 02001525A EP 1237393 A2 EP1237393 A2 EP 1237393A2
Authority
EP
European Patent Office
Prior art keywords
magnetic circuit
speaker
voice coil
bottom portion
air
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02001525A
Other languages
English (en)
French (fr)
Inventor
Takashi c/o Tohoku Pioneer Corporation Kaiwa
Osamu c/o Tohoku Pioneer Corporation Takahashi
Masanori c/o Tohoku Pioneer Corporation Ito
Kunio c/o Tohoku Pioneer Corporation Mitobe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tohoku Pioneer Corp
Pioneer Corp
Original Assignee
Tohoku Pioneer Corp
Pioneer Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tohoku Pioneer Corp, Pioneer Corp filed Critical Tohoku Pioneer Corp
Publication of EP1237393A2 publication Critical patent/EP1237393A2/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/022—Cooling arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
    • H04R9/02—Details
    • H04R9/025—Magnetic circuit

Definitions

  • This invention relates to an electrically driven speaker and speaker system used in various audio systems, especially a speaker appropriate to be used for mounting in a casing of a small-size equipment and a speaker system to be constituted with a speaker mounted in a casing.
  • An electrically driven speaker is used generally in various audio systems, up to now.
  • An electrically driven speaker has two types according to magnetic circuit structures, i.e., an outer magnet type and an inner magnet type defined by a magnet position in a magnetic circuit.
  • respective vibrating member of two-type speakers has almost same structural relation for a magnetic circuit.
  • An electrically driven speaker a half-section shown in Fig. 9, is provided with an outer-magnet-type magnetic circuit comprising an annular top plate 1 having an opening 1a in the center, an annular magnet 2 attached to a bottom surface of the top plate 1 and magnetized in a direction of thickness, and a yoke 3 attached to a bottom surface of the magnet 2.
  • the yoke 3 is provided with a bottom plate 3a, and a center pole 3b projecting from the center of the bottom plate 3a and forming a gap G between an inner circular surface of the opening 1a in the top plate 1.
  • mark 5 shows a frame attached to a top surface of the top plate 1
  • mark 6 shows a voice coil supported in the magnetic gap G and vibrating correspondingly to electrical signals
  • mark 7 shows a cylindrical voice coil bobbin transmitting driving force generated in the voice coil 6 to a vibrating system
  • mark 8 shows a vibrating member attached to a top edge of the voice coil bobbin 7
  • mark 9 shows a damper joined at an inner circular portion thereof to an intermediate position of the voice coil bobbin 7 and joined at an outer circular portion thereof to the frame 5
  • mark 10 shows a roll-shape edge joined at an inner circular portion to an outer circular portion of the vibrating member 8 and joined at an outer circular portion thereof to the frame 5.
  • the voice coil 6, the voice coil bobbin 7, the vibrating member 8, the damper 9 and the edge 10 constitute a vibration system 12.
  • a space A enclosed with the cylindrical voice coil bobbin 7 describing in detail, a space A formed by a top surface of the center pole 3b, an inner circular surface of the voice coil bobbin 7 and a bottom surface of the vibrating member 8; is ventilated through a thin gap g1 formed by an outer circular surface of the center pole 3b and an inner circular surface of the voice coil bobbin 7 to a space B formed by an outer circular surface of the center pole 3b, a top surface of the bottom plate 3a, an inner circular surface of the magnet 2, and a bottom surface of the top plate 1.
  • the space A is ventilated through a thin gap g2 formed by an inner circular surface of the top plate 1 and an outer circular surface of the voice coil bobbin 6, and a ventilating opening 5a provided in the air-permeable damper 9 and in the frame 5 to an outside of the frame 5, i.e. an outside space of the speaker.
  • the above structured speaker When the above structured speaker is inputted with a large power, a large electric current runs in the voice coil 6 so as to be heated.
  • the heat, generated in the voice coil is transmitted through air of a space between an outer circular surface of the center pole 3b and an inner circular surface of the voice coil bobbin 7 to the center pole 3b, and transmitted through air of a space between an inner circular surface of the top plate 1 and an outer circular surface of the voice coil 6 to the top plate 1, and then refrigerated. Furthermore, the heat is also refrigerated by air moving in the thin gap g2 formed by an inner circular surface of the top plate 1 and an outer circular surface of the voice coil 6.
  • the heat conductivity of air is low and ventilation between the space A and an outside space of the speaker is done through the thin gap g1 formed by an outer circular surface of the center pole 3b and an inner circular surface of the voice coil bobbin 7 so that the ventilation is not enough to refrigerate sufficiently the heat of the voice coil 6. Therefore, electric resistance of the voice coil 6 increases by heating and electric current goes down then sound pressure corresponding to electric input can not be given.
  • a speaker It is proposed on a speaker to provide a throughhole C, as shown in Fig. 9, through the center of a center pole 3b, extending from a top surface of the center pole 3b to a bottom surface of a bottom plate 3a, communicating between a space A and an outside of a magnetic circuit, to improve releasing heat generated in a voice coil 6 and transmitted to a center pole 3b for reducing temperature rising of the voice coil 6 and increasing allowable input power.
  • ventilation between a space A and an outside of a magnetic circuit is done through the throughhole so that the expansion/compression coefficient of air is decreased and then sound distortion by non-linearity of air compliance is restrained.
  • a cylindrical magnet 31 is provided on a center of a top surface of a bottom plate 30a forming a bottom portion of a bottomed cylindrical yoke 30 and a disk-shaped pole piece 32 forming a magnetic gap G between an inner circular surface of the yoke 30 is joined on the magnet 31.
  • the inner-magnet-type magnetic circuit is provided with a throughhole C through the pole piece 32, the magnet 31 and yoke 30, communicating between a space A and an outside of a magnetic circuit, to improve releasing heat, generated in a voice coil 6 and transmitted to the pole piece 32, for reducing temperature rising of the voice coil 6 and increasing allowable input power so that the expansion/compression coefficient of air is decreased and then sound distortion by non-linearity of air compliance is restrained.
  • a speaker is shown simply with a vibration system and a magnetic circuit in Fig. 11 and mounted to be held between inner surfaces of a casing 20 by facing a surface of the vibration system 4 and a bottom portion of the magnetic circuit 12 respectively to inner surfaces of the casing 20.
  • a sounding surface of the vibration system 4 is placed to abut on an inner surface of a front wall 21, having a sounding opening 21a, of the casing 20 and is pressed by an elastic-material-made pad 23 inserted between an inner surface of a rear wall 22, parallel to the front wall 21, of the casing 20 and a bottom surface of the speaker magnetic circuit 12 so that the speaker is mounted and fixed in the casing.
  • pressing the bottom surface of the speaker magnetic circuit 12 directly by the inner surface of the rear wall 22 of the casing 20, as shown in Fig. 12 the speaker is mounted and fixed in the casing.
  • a casing for mounting a speaker is miniaturized and a structure which a speaker is mounted in a casing to be held between inner surfaces by facing a surface of a vibration system and a bottom portion of a magnetic circuit respectively to the inner surfaces of the casing, as shown in Fig. 10 or 11, is applied so that a throughhole, formed in a magnetic circuit to communicate with a space enclosed with a voice coil bobbin, is blocked at a bottom portion of a magnetic circuit by the pad 23 or the inner surface of the rear wall 22. Therefore, air in a space A enclosed with a voice coil bobbin can not be ventilated through a throughhole C from a bottom portion of a magnetic circuit 12.
  • the throughhole C can not perform the function to restrain sound distortion by non-linearity of air compliance by improving releasing heat, generated in a voice coil 6 and transmitted to the pole piece 32, for reducing temperature rising of the voice coil 6 and increasing allowable input power.
  • This invention has been accomplished to overcome the above drawbacks and an object of this invention is to provide a speaker enabled to ventilate air in a space enclosed with a voice coil bobbin to outside of a magnetic circuit through a throughhole formed in the magnetic circuit to communicate with the space even if the speaker is mounted and fixed between inner surfaces in a casing to face a surface of a vibration system and a bottom portion of the magnetic circuit respectively to inner surfaces of the casing.
  • Another object is to provide a speaker system enabled to ventilate air in a space enclosed with a voice coil bobbin to an outside of a magnetic circuit through a throughhole formed in the magnetic circuit to communicate with the space even if the speaker is mounted and fixed between inner surfaces in a casing to face a surface of a vibration system and a bottom portion of the magnetic circuit respectively to inner surfaces of the casing.
  • a speaker which includes a vibration system having a voice coil, a cylindrical voice coil bobbin carrying said voice coil and a vibrating member attached to said voice coil bobbin, and a magnetic circuit generating magnetic force in cooperating with the voice coil to drive said vibrating member, a throughhole formed through said magnetic circuit to communicate with a space enclosed with the voice coil bobbin for ventilating air in said space from a bottom portion of the magnetic circuit; for being used to be fixed between inner surfaces of a casing-by facing a surface of the vibration system and a bottom portion of the magnetic circuit respectively to the inner surfaces, and comprises an air path formed in the magnetic circuit to communicate with said throughhole for ventilating air in the space to outside of the magnetic circuit.
  • air in the space enclosed with the voice coil bobbin can be ventilated to outside of the magnetic circuit through the air path formed in the magnetic circuit to communicate with the throughhole for ventilating air in the space from a bottom portion of the magnetic circuit so that air in the space can be ventilated to outside of the magnetic circuit even if the throughhole is blocked by fixing between the inner surfaces of the casing to face the surface of the vibration system and the bottom portion of the magnetic circuit respectively to the inner surface.
  • a speaker which comprises a speaker as referred to above, wherein said air path is formed in the bottom portion of said magnetic circuit.
  • a speaker which comprises a speaker as referred to above, wherein said air path is formed, in the bottom portion of the magnetic circuit, extending to an outer edge of the bottom portion of the magnetic circuit.
  • air ventilation through the air path, formed in the bottom portion of the magnetic circuit extending to an outer edge of the bottom portion of the magnetic circuit, is kept even if the bottom portion of the magnetic circuit is pressed with any members for fixing between inner surfaces of the casing. So it is no chance that air in the space cannot be ventilated to outside of the magnetic circuit caused by blocking the throughhole.
  • a speaker which comprises a speaker as referred to above, wherein said air path is formed, in the bottom portion of the magnetic circuit, extending to an area of the bottom portion of the magnetic circuit which can not be blocked by the inner surfaces of the casing.
  • a speaker which comprises a speaker as referred to above, wherein said magnetic circuit is outer-magnet-type and said throughhole is formed extending to the bottom portion of the magnetic circuit through a center pole of said magnetic circuit.
  • a speaker which comprises a speaker as referred to claim 2, wherein said magnetic circuit is inner-magnet-type and said throughhole is formed extending to the bottom portion of the magnetic circuit through a pole piece and a magnet of said magnetic circuit.
  • a speaker system which includes a speaker comprising a vibration system having a voice coil, a cylindrical voice coil bobbin carrying said voice coil and a vibrating member attached to said voice coil bobbin, and a magnetic circuit generating magnetic force in cooperating with the voice coil to drive said vibrating member, and a casing for receiving said speaker, wherein said speaker is fixed between inner surfaces of said casing by facing a surface of said vibration system and a bottom portion of said magnetic circuit respectively to said inner surfaces, wherein a path is formed in said magnetic circuit to communicate with a space enclosed with the voice coil bobbin for ventilating air in said space from a bottom portion of the magnetic circuit.
  • air in the space enclosed with the voice coil bobbin can be ventilated to outside of the magnetic circuit through the path formed in the magnetic circuit even if the speaker, having a vibration system including a voice coil, a cylindrical voice coil bobbin and a vibrating member, and a magnetic circuit, is fixed between the inner surfaces of the casing by facing the surface of the vibration system and a bottom portion of the magnetic circuit respectively to the inner surface. So it is no chance that air in the space cannot be ventilated to outside of the magnetic circuit.
  • a speaker system which comprises a speaker system as referred to above, and said path provided with a throughhole formed through said magnetic circuit to communicate with a space enclosed with said voice coil bobbin for ventilating air in said space from a bottom portion of said magnetic circuit, and an air path formed, in the bottom portion of the magnetic circuit, to communicate with said throughhole for ventilating air in said space to outside of the magnetic circuit.
  • air in the space can be ventilated to outside of the magnetic circuit through the throughhole formed through the magnetic circuit for ventilating air in the space from a bottom portion of the magnetic circuit and the air path formed in the bottom portion of the magnetic circuit, to communicate with the throughhole for ventilating air in the space to outside of the magnetic circuit. So it is no chance that air in the space cannot be ventilated to outside of the magnetic circuit.
  • a speaker or a speaker system having no chance of disabled ventilating air in a space enclosed with a voice coil bobbin to outside of the magnetic circuit through a throughhole formed in a magnetic circuit to communicate with the space enclosed with a voice coil bobbin, even if mounting a speaker between inner surfaces of a casing, facing a surface of a vibration system and a bottom portion of a magnetic circuit to inner surfaces of the casing.
  • a speaker and a speaker system, having a speaker in a casing, of embodiments according to this invention will be described with reference to the attached drawings. Parts corresponding to a speaker and a speaker system shown in Fig. 9-12 are shown with the same marking.
  • Fig. 1A and 1B show an example of outer-magnet-type magnetic circuits able to be used in a speaker according to this invention.
  • Fig. 1A is a sectional view and Fig. 1B is a bottom view.
  • a groove 3c is provided by machining or press working, through a center of a bottom plate 3a, extending an outer circular edge of the bottom plate 3a, on the bottom surface of the bottom plate 3a of a yoke 3 constituting a magnetic circuit.
  • the groove 3c communicates with a throughhole C through a center of a center pole 3b, opened from a top surface of the center pole 3b to the center of the bottom surface of the bottom plate 3a.
  • a sounding surface of a vibration system 4 of a speaker is abutted on an inner surface of a front wall, having a sounding opening 21a, of a casing 20 and placed in position and then, a bottom surface of a magnetic circuit 12 of the speaker is pressed by an elastic-material-made pad 23 inserted between an inner surface of a rear wall 22 and the bottom surface of the magnetic circuit 12 as shown in Fig.2, or pressed directly by an inner surface of the rear wall 22 of the casing 20 as shown in Fig. 3 so that the throughhole C is not blocked.
  • air ventilation between outside can be done through an air path formed by a throughhole and a groove to exhaust air in a space enclosed with not-shown voice coil bobbin to outside of the magnetic circuit and to take air at outside of the magnetic circuit into the space so that improving releasing heat and reducing temperature rising of the voice coil and increasing allowable input power, the expansion/compression coefficient of air is decreased and then sound distortion by non-linearity of air compliance can be restrained.
  • the air path is given by a groove 3c formed on the bottom surface of the bottom plate 3a by machining or press working, extending an outer circular edge of the bottom plate 3a to communicate with the throughhole C.
  • the air path may be given with a concave portion provided between a pair of parallel ribs formed projectionaly on the bottom surface of the bottom plate.
  • a groove 3c is formed in a straight line extending an outer circular edge of the bottom plate 3a through the center thereof.
  • the groove may be formed in cross-shape as shown in Fig. 4 or formed in a radial pattern as shown in Fig. 5 to improve air ventilation within the limits of not affecting magnetic function and strength of the yoke 3.
  • Fig. 6A and 6B show an example of inner-magnet-type magnetic circuits able to be used in a speaker according to this invention.
  • Fig. 6A is a sectional view and Fig. 6B is a bottom view.
  • a slit opening 30c is provided by machining or punching before forming cylindrical shape, through a center of a bottom plate 30a, extending an outer circular edge of the bottom plate 30a, on the bottom surface of the bottom plate 30a forming a bottom portion of a bottomed cylindrical yoke 30 constituting a magnetic circuit.
  • the slit opening 30c communicates in a bottom plate 30a with a throughhole C opened through a pole piece 30b, a magnet 31 and the yoke 30.
  • the throughhole C is not blocked and air ventilation between outside can be done through an air path formed by the slit opening 30c to communicate with the throughhole C and extend to the outer circular edge of the bottom plate 30a to exhaust air in a space enclosed with not-shown voice coil bobbin to outside of the magnetic circuit and to take air at outside of the magnetic circuit into the space. Therefore, in the speaker, releasing heat is improved and temperature rising of the voice coil is reduced and allowable input power is increased so that the expansion/compression coefficient of air is decreased and then sound distortion by non-linearity of air compliance can be restrained.
  • the slit opening 30c is formed in a straight line, extending an outer circular edge of the bottom plate 30a through the center thereof.
  • the slit opening may be formed in cross-shape or a radial pattern as mentioned above in Fig. 4 and 5 to improve air ventilation within the limits of not affecting magnetic function and strength of the yoke 30.
  • the slit opening 30c is formed on the bottom plate 30a to provide a air path having a height as same as a thickness of the bottom plate 30a so that the slit opening preferably perform also an air path communicating with a space B, formed around an outer circular surface of the magnet, to improve releasing heat.
  • the air path may be formed in a groove as same as the example in Fig. 1.
  • the slit opening 30c is formed in a straight line, extending an outer circular edge of the bottom plate 30a through the center thereof.
  • a square opening 30c' as shown in Fig. 7, may be formed to have a larger area than a pad 23 and keep an outer circular edge portion of the bottom plate 30a instead of the slit opening 30c when the pad 23, inserted between a inner surface of the rear wall 22 and a bottom surface of the magnetic circuit 12 of the speaker for pressing the bottom surface thereof, is enough smaller than an area of the bottom surface of the magnetic circuit 12.
  • Such square opening 30c' can be manufactured easier than a slit opening extending to an outer circular edge and also is advantageous to keep strength of a yoke.
  • An air path formed by such square opening 30c' faces to a rear surface direction facing to an inner surface of a casing as shown in Fig. 8, opposing above-mentioned embodiment which an air vent is on a side of the magnetic circuit.
  • an air path is formed in a magnetic circuit to communicate with a throughhole provided in the magnetic circuit to exhaust air in a space enclosed with a voice coil bobbin to outside of the magnetic circuit so that a casing for mounting a speaker can be miniaturized.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
EP02001525A 2001-02-28 2002-01-22 Lautsprecher und Lautsprechersystem Withdrawn EP1237393A2 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2001055161 2001-02-28
JP2001055161A JP2002262387A (ja) 2001-02-28 2001-02-28 スピーカ及びスピーカ装置

Publications (1)

Publication Number Publication Date
EP1237393A2 true EP1237393A2 (de) 2002-09-04

Family

ID=18915383

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02001525A Withdrawn EP1237393A2 (de) 2001-02-28 2002-01-22 Lautsprecher und Lautsprechersystem

Country Status (4)

Country Link
US (1) US6754362B2 (de)
EP (1) EP1237393A2 (de)
JP (1) JP2002262387A (de)
CN (1) CN1250044C (de)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003289596A (ja) * 2002-03-27 2003-10-10 Citizen Electronics Co Ltd スピーカ及びその製造方法
JP4508827B2 (ja) * 2003-10-31 2010-07-21 富士通テン株式会社 板体直接駆動振動装置
JP2005348389A (ja) * 2004-05-07 2005-12-15 Pioneer Electronic Corp スピーカ
JP3966318B2 (ja) * 2004-09-09 2007-08-29 セイコーエプソン株式会社 電気光学装置及び電子機器
JP2006217452A (ja) * 2005-02-07 2006-08-17 Matsushita Electric Ind Co Ltd スピーカ
JP4723999B2 (ja) * 2005-12-28 2011-07-13 パイオニア株式会社 スピーカ及びスピーカユニット
JP5033408B2 (ja) * 2006-12-12 2012-09-26 株式会社オーディオテクニカ ダイナミックマイクロホン
JP5014883B2 (ja) * 2007-06-06 2012-08-29 ミネベア株式会社 スピーカ
US20110044491A1 (en) * 2009-08-23 2011-02-24 Plastoform Industries Ltd. Long excursion loudspeaker with closed magnetic circuit and ribbed robbin extending through slotted yoke
WO2015136656A1 (ja) * 2014-03-13 2015-09-17 賢太 田中 スピーカ装置
CN106162457A (zh) * 2016-07-11 2016-11-23 深圳天珑无线科技有限公司 扬声器及移动设备
CN109495819B (zh) * 2018-11-02 2020-11-20 歌尔股份有限公司 发声装置和耳机

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3163902B2 (ja) * 1994-06-16 2001-05-08 ソニー株式会社 スピーカ装置
US5909015A (en) * 1998-03-26 1999-06-01 Yamamoto; Shuji Self-cooled loudspeaker
US6243479B1 (en) * 1999-12-08 2001-06-05 Lucio Proni Loudspeaker having pole piece with integral vent bores
US20010031063A1 (en) * 1999-12-21 2001-10-18 Jassa Langford Loudspeaker free flow cooling system

Also Published As

Publication number Publication date
CN1373629A (zh) 2002-10-09
US6754362B2 (en) 2004-06-22
US20020118855A1 (en) 2002-08-29
JP2002262387A (ja) 2002-09-13
CN1250044C (zh) 2006-04-05

Similar Documents

Publication Publication Date Title
EP2408219B1 (de) Mikrolautsprecher
US8189841B2 (en) Acoustic passive radiating
US7747034B2 (en) Speaker device
EP0618752B1 (de) Lautsprecherstruktur
US6754362B2 (en) Speaker and speaker system
EP1944999B1 (de) Lautsprecher, lautsprechervorrichtung mit dem lautsprecher sowie elektronisches gerät und fahrzeug mit dem lautsprecher
EP1484941A1 (de) Lautsprecher
WO2006064725A1 (ja) スピーカ
JP2006217452A (ja) スピーカ
JP2002171596A (ja) スピーカ装置
EP1942701B1 (de) Lautsprecher
KR20180042757A (ko) 스피커 및 스피커의 제조방법
US7272238B2 (en) Loudspeaker having cooling system
US8022799B2 (en) Thin multi-function vibration actuator
JP2003143692A (ja) 携帯端末機用の双方向スピーカ
US7634102B2 (en) Speaker and device using the same
US20090003644A1 (en) Electroacoustic transducer
JP2005277874A (ja) 同軸スピーカー装置及びその製造方法
WO2003024151A1 (en) An electro-acoustic transducer with two diaphragms
US7035425B2 (en) Frequency response enhancements for electro-dynamic loudspeakers
EP1737269A1 (de) Flacher Lautsprecher
KR20220025035A (ko) 스피커유닛 및 스피커 만곡진동판
CN107948802B (zh) 一种受话器
KR200338060Y1 (ko) 보이스 코일이 결합된 피에조 세라믹 진동판을 이용한 다기능 전자 음향 변환기의 구조
JP2004048432A (ja) スピーカ

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20080801